Fig.1 Distribution map of Meso-Neoproterozoic troughs in the North China Craton (a) (modified after [25]) and tectonic location map of the Qinshui Basin (b)

Fig.2 Cross-sectional map of the Meso-Neoproterozoic stratigraphic correlation between the Yanliao Basin and the Xiong’er Basin in the North China Craton. Modified after [54].

Fig.3 Tectonic evolution model of the Xiong’er Basin and Yanliao Basin in the North China Craton during the Changcheng Period. Modified after [47].

Fig.4 Comparative stratigraphic section of the Precambrian field outcrop in the eastern part of the Qinshui Basin (modified after [46]; the location of the outcrop is shown in Fig.1b)

Fig.5 Comparative stratigraphic section of Precambrian field outcrops in the southern part of the Qinshui Basin (modified after [46]; the location of the outcrop is shown in Fig.1b)

Fig.6 Reflection characteristics of Precambrian sedimentary strata on typical seismic sections in the southern Qinshui Basin (profile location shown in Fig.1b)

Fig.7 Occurrence characteristics of sedimentary strata of the Changcheng System in the Henghe area on the southern edge of the Qinshui Basin a—Field outcrop profile of the Beidajian Formation in the Henghe area (location shown in Fig.7b); b—Regional geological map of the Henghe area (location shown in Fig.1b, based on internal data from Huabei Oilfield).

Fig.8 Comprehensive columnar chart of Precambrian stratigraphy and seismic reflection characteristics of corresponding strata in the Qinshui Basin and its periphery

Fig.9 Geological interpretation of a typical seismic profile in the Qinshui Basin (location of the seismic profile shown in Fig.1b)

Fig.10 Profile position and planar distribution of the pinch-out line of the Precambrian sedimentary strata in the southern Qinshui Basin (the scope of the two-dimensional seismic work area is shown in Fig.1b, the location of the seismic profile is shown in Fig.10a, and the thick red line in the figure indicates a fault)

Fig.11 Residual thickness isochronous maps of each formation of the Precambrian in the southern Qinshui Basin (the scope of the two-dimensional seismic work area is shown in Fig.1b) a—Residual thickness isochronous map of the Yunmengshan Formation of the Changcheng System; b—Residual thickness isochronous map of the Baicaoping Formation of the Changcheng System; c—Residual thickness isochronous map of the Beidajian Formation of the Changcheng System; d—Residual thickness isochronous map of the Cuizhuang Formation of the Changcheng System; e—Residual thickness isochronous map of the Luoyukou Formation of the Changcheng System; f—Residual thickness isochronous map of the Longjiayuan Formation of the Jixian System.

Fig.12 Field outcrop photos of Precambrian source rocks around the Qinshui Basin. a—Dark gray shale of the Chuanlinggou Formation of the Changcheng System, outcrop at Dajingpan, Licheng, on the western side of the Qinshui Basin; b—Dark gray shale of the Cuizhuang Formation of the Changcheng System, outcrop at Shuiyou, Yongji, on the southern side of the Qinshui Basin; c—Black dolomite of the Longjiayuan Formation of the Jixian System, outcrop at Shuiyou, Yongji, on the southern side of the Qinshui Basin; d—Black dolomite of the Longjiayuan Formation of the Jixian System, outcrop at Shuiyou, Yongji, on the southern side of the Qinshui Basin.

Fig.13 Seismic facies classification of the Cuizhuang Formation and Longjiayuan Formation in the southern Qinshui Basin

Fig.14 Seismic and sedimentary facies distribution map of the Cuizhuang Formation and Longjiayuan Formation in the southern Qinshui Basin (the scope of the two-dimensional seismic work area is shown in Fig.1b)

Fig.15 Prediction of favorable hydrocarbon-generating areas in the Cuizhuang Formation of the Changcheng System and the Longjiayuan Formation of the Jixian System in the southern Qinshui Basin (the scope of the two-dimensional seismic work area is shown in Fig.1b)